list L := X, A + B
list M := for I := 1 step 1 until N do A[I] .
A list identifier may itself appear in a list. One of the above examples might be written with the aid of the following declaration:
list L := for J := 1 step 1 until 20 do B[I,J] .
The loop expression is then
for I:= 1 step 1 until 10 do (A[I], L) .
A list declaration obeys the same rules of syntax and scope as do other declarations.
A list identifier may be used as an actual parameter of a procedure call, with the requirement that the corresponding formal parameter be specified list. However, an actual list may appear as a parameter only in calls of the standard procedures, as described.
The PRINT procedure is used to output numbers in a simple, rigid manner. A PRINT statement has the form